21947902 has 8 divisors (see below), whose sum is σ = 32988816. Its totient is φ = 10951632.

The previous prime is 21947897. The next prime is 21947903. The reversal of 21947902 is 20974912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21947903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9903 + ... + 11914.

It is an arithmetic number, because the mean of its divisors is an integer number (4123602).

Almost surely, 2^21947902 is an apocalyptic number.

21947902 is a deficient number, since it is larger than the sum of its proper divisors (11040914).

21947902 is a wasteful number, since it uses less digits than its factorization.

21947902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22322.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 21947902 is about 4684.8588025681. The cubic root of 21947902 is about 279.9825754463.

The spelling of 21947902 in words is "twenty-one million, nine hundred forty-seven thousand, nine hundred two".